Announcement of Results from a Single Dose Phase 1 Study of a Human Monoclonal Anti-FGF23 Antibody (KRN23) in X-linked Hypophosphatemia in Adults
October 7, 2013
Tokyo, Japan, October 7, 2013 -- Kyowa Hakko Kirin Co., Ltd. (Tokyo; 4151, President and CEO: Nobuo Hanai, "Kyowa Hakko Kirin") announced that results from a first-in-human, single dose Phase 1 study of a human monoclonal anti-FGF23 antibody (KRN23) in X-linked hypophosphatemia (XLH) in adults were presented at the American Society of Bone Mineralization Research (ASBMR) 2013 Annual Meeting on October 6, 2013. A randomized, double-blind, placebo-controlled, Phase I study (US-02) was conducted to assess its safety, tolerability, pharmacokinetics and pharmacodynamics in adult patients with XLH. Thirty-eight adults with XLH were randomized to receive single doses of KRN23 or placebo via intravenous (IV) (0.003 to 0.3 mg/kg) or subcutaneous (SC) (0.1 to 1.0 mg/kg) routes.
Data were presented by Thomas Carpenter, MD, Yale University at the ASBMR 2013 Annual Meeting. The study showed single doses of either IV or SC KRN23 increased serum phosphate level compared to placebo for higher doses (p<0.01). Peak serum phosphate effects occurred later with SC (8-15 days) than with IV dosing (0.5-4 days). Duration of effect on phosphate was dose-related, greater with SC than IV, and persisted beyond 29 days with SC. Increases in renal reabsorption of phosphate and 1,25 dihydroxyvitamin D were observed. No meaningful changes in serum calcium, serum parathyroid hormone, and urinary calcium excretion occurred. The majority of adverse events were mild, and there were no serious adverse events, and no changes in safety biochemistries, electrocardiograms, or renal sonograms. No patient developed anti-KRN23 antibodies. Single dose administration of KRN23 was safe and well-tolerated.
Kyowa Hakko Kirin has a collaboration and license agreement with Ultragenyx Pharmaceutical Inc. ("Ultragenyx") to jointly develop and commercialize KRN23. Kyowa Hakko Kirin and Ultragenyx plan to continue the development of KRN23 in adult XLH patients while initiating a pediatric XLH program in 2014.
- About KRN23 and FGF23
- KRN23 is a recombinant fully human monoclonal IgG1 antibody discovered by KHK and being developed to treat X-linked hypophosphatemia (XLH). KRN23 is designed to bind to and thereby reduce the biologic activity of fibroblast growth factor 23 (FGF23). FGF23 is a hormone that promotes phosphate excretion by the kidney and suppresses vitamin D production. FGF23 also reduces the expression of the enzyme that is required to synthesize a hormone that normally increases renal tubular absorption of both phosphate and calcium. Therefore, FGF23 induces profound reductions in serum phosphate levels. Phosphate wasting in XLH is caused by excessive levels and activity of FGF23.
- About X-linked Hypophosphatemia (XLH)
- XLH is a disorder of phosphate metabolism caused by phosphate wasting in the urine leading to severe hypophosphatemia. XLH is the most common heritable form of rickets that is inherited as an X-linked dominant trait affecting both males and females, though the disease in males by some reports may be more severe. XLH is a distinctive bone disease characterized by inadequate mineralization of bone that leads to a spectrum of abnormalities, including progressive bowing of the leg, osteomalacia, bone pain, waddling gait, short stature, gross motor impairment, muscle weakness, osteopenia, frequent/poorly healing microfractures, spinal stenosis and osteoarthritis.
Most patients are managed using oral phosphate replacement and vitamin D (calcitriol) therapy, which is poorly tolerated and only partially effective at restoring bone physiology and growth. Current treatment with oral phosphate requires extremely close monitoring and can result in complications such as secondary hyperparathyroidism, hypercalciuria, hypercalcemia and nephrocalcinosis. XLH was originally called vitamin D-resistant rickets, because doses of vitamin D effective for the treatment of vitamin D-deficient nutritional rickets did not have an impact on phosphate levels in these patients.
- About Ultragenyx Pharmaceutical Inc.
- Ultragenyx is a privately held, clinical-stage biotechnology company committed to bringing to market life-transforming therapeutics for patients with rare and ultra-rare metabolic genetic diseases. Founded in 2010, the company is rapidly building a diverse portfolio of product candidates with the potential to address diseases for which the unmet medical need is high, the biology for treatment is clear, and for which there are no effective treatments.
The company is led by a management team experienced in the development and commercialization of rare disease therapeutics. Ultragenyx's strategy is predicated upon time and cost-efficient drug development, with the goal of delivering safe and effective therapies to patients with the utmost urgency.
For more information on Ultragenyx, please visit the company's website at www.ultragenyx.com.
Kyowa Hakko Kirin